Web dryer



July 4, 1967 R. C. KRONE ET L WEB DRYER 5 Shets-$heet 1 Filed April July4, 1967 Filed April 30, 1964 FIE.E

R. C. KRONE ET AL WEB DRYER 5 Sheets-Sheet 2 R. C. KRONE ET AL July 4,1967 WEB DRYER v 5 Sheets-Sheet 3 Filed April 30, 1964 July 4, 1967Filed April 30, 1964 R. C. KRONE ET AL WEB DRYER 5 Sheets-Sheet 4 July4, 1967 Q KRONE ET AL 3,328,895

WEB DRYER Filed April 30, 1964 5 Sheets-Sheet 5 3,328,895 WEB DRYERRobert C. Krone, Elmhurst, and Louis J. Hansen, La Grange Park, Ill.,assignors to R. R. Donnelley & Sons Company, a corporation of DelawareFiled Apr. 30, 1964, Ser. No. 363,801 8 Claims. (Cl. 3468) Thisinvention relates to a system for drying printed webs and especiallypaper Webs.

In the printing of paper for use as leaves of booklets, pamphlets andthe like, it is common practice to process the paper in a generallycontinuous web form, e.g. from a roll, in a manner including the stepsof printing the first side of the web, drying the ink on the printedfirst side, printing the second side of the web and then drying the inkon the printed second side. In such processing, the paper is directedthrough a web travel path at a fast rate, and after the second side isdried, the web is cut to proper leaf size, and further processed to formthe desired finished product.

During the drying of the printed web, heating chambers, includingburners, are often used; and the web is directed by a web directingsystem into heat receiving proximity to the burners and heating chambersfor removal of volatiles from the ink to dry the ink. Because highproduction rates are required, the burners are usually designed to putout a large quantity of heat, often with the burner flame directedtoward the printed web. Inability to maintain even burner heat outputoften results in scorching of the paper web, thereby greatly detractingfrom the saleability of the product.

Additionally, the volatile solvents in the ink composition are generallyflammable and may tend to collect in the heating chambers inconcentrations above the explosive limit, thereby creating hazardousconditions of operation. Also, solvents tend to leak from the heatingchambers, e.g. adjacent the web, or may be carried from the heatingchambers by the traveling Web into the surrounding atmosphere, undulycontaminating the atmosphere.

It has been found desirable to circulate air through the heatingchambers to remove volatiles and decrease the explosion hazard.Circulation of air, and especially cold air, through the heatingchambers and against the burners often chills and extinguishes theburners. A balanced amount of air circulation which will provideadequate carry-off of explosive volatiles and still permit elficientburner operation is, in some cases at least, very diliicult to achieve,if not impossible.

Volatiles which escape from the heating chambers may condense on the webor portions of the web directing system, such as the cool surfaces ofdrums and rollers in contact with the web. The condensed volatilesolvents may smear or otherwise detract from the printed material on theWeb.

It is an object of this invention to provide a new and useful system fordrying printed webs, and especially paper webs.

It is another object of this invention to provide such a system in whichheating chambers are adequately purged of volatile solvents withoutsubstantially decreasing the heating efliciency of the burner.

Still another object is to provide such a system in which volatilescarried from the heating chamber by the traveling web are collected toprevent contamination of the atmosphere.

It is another object of this invention to minimize or decrease thecollection of condensible volatiles on components of the web directingsystem by means provided in association with the web travel path forremoving volatiles from adjacent the web and from adjacent the webdirecting system.

United States Fatent Yet another object of this invention is to providesuch a system wherein a heated recirculated air stream is directed overthe face of the web being dried to carry off solvents and preventflash-off, while eliminating buildup of solvents in heating chambers andin exhaust systems to concentrations above the explosive limits.

It is a feature of the present invention, in one form thereof, thatthere is provided a recirculating cyclic stream of hot air which isdirected through a plurality of heater boxes to vent volatile solventstherefrom and which is withdrawn from the boxes, subjected to solventremoval procedures and returned or recycled at least in part as a cyclicstream through the boxes. In the preferred application of the principlesof the present invention, an air knife system is provided adjacent theoutlet of each heater box for directing volatiles into the heater boxoutlet for recycle. Also, in the preferred form, an air blade system isoperated on the reverse or non-drying side of the Web to divertvolatiles carried by the web into an exhaust system for return to thecyclic stream, and a further exhaust chamber system is provided forremoval of vaporized solvent adjacent the reverse side of the paper webbeyond the heating chamber where the web is directed away from theheating chamber. The air knife system and exhaust chamber on the reverseside of the web also function to block or inhibit flow of condensiblevolatiles to prevent them from condensing on the web directing system.

Other objects and features of the present invention will be apparentfrom the following description and the drawings, in which:

FIGURE 1 is a schematic longitudinal sectional showing of a web dryingsystem in accordance with the present invention;

FIGURE 2 is a flow diagram and schematic showing of duct work andassociated equipment for maintaining a cyclic stream of hotrecirculating air which is directed through a plurality of heater boxesin parallel flow in the system of FIGURE 1;

FIGURE 3 is a fragmentary longitudinal sectional view on an enlargedscale of a heater box of the system of FIG- URE 1;

FIGURE 4 is a fragmentary longitudinal sectional View takensubstantially as indicated along the line 4-4 of FIGURE 5, showingdetails of the inlet and outlet mani' folds of the heater box of FIGURE3 on an enlarged scale;

FIGURE 5 is a fragmentary section taken substantialas indicated alongthe line 5-5 of FIGURE 4; FIGURE 6 is a fragmentary side elevation on anenlarged scale, and partially in section, illustrating a burner element;

FIGURE 7 is a section taken substantially as indicated along the line 77of FIGURE 6; and

FIGURE 8 illustrates an exhaust chamber system for collecting vaporsfrom adjacent the reverse side of the paper web.

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawings and will herein be described indetail a specific embodiment of the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit theinvention to the embodiment illustrated.

Turning first to FIGURE 1, there is illustrated a system for drying anink-printed web W, e.g of paper, immediately after printing of the webon each surface. The drying system includes separate web heating anddrying sections 11 and 12, one for drying each side of the web. The webis maintained or supported in its web travel position as indicated inFIGURE 1 by ,a plurality of driven chill rollers or water rollers 13 ofnormal construction having an internal cavity filled with cooling water.A driven water drum 14, also similarly water cooled, is provided beyondeach of the heating sections 11 and 12 for directing the web W away fromthe respective heating sections.

The separate web drying and heating sections 11 and 12 are used to dryopposite sides of the web W. Thus, after a first side of web W isprinted, the web passes over rollers 13 and water drum 14 of the webdrying section 11 with the printed side facing away from the rollers anddrum, thence away from the web drying section 11 to a press which printsthe second side of the web, and then from the press over the rollers 13and drum 14 of drying section 12 with the freshly printed second side ofthe web disposed outwardly with respect to the rollers 13 and drum 14 ofweb drying section 12. The path in which the web is carried on therollers 13 and drum 14 in each of drying sections 11 and 12 will bereferred to herein as the web travel path.

Referring now to FIGURES l and 3, each of the web drying sections 11 and12 includes a linear array of heating chambers 17 defined by casingwalls 18 and each having an open lower side 19 facing the web travelpath so that the freshly printed surface of web W is subjected to heatfrom the chambers.

Each of heating chambers 17 is fed with heated secondary air through aninlet duct 20 which terminates in a nozzle end 21 for directing theheated air over the freshly printed surface of web W toward an outletduct 22 at the other end of chamber 17. A plurality of inverted burners23 is provided in each chamber 17 facing the web travel path andsupplied with a combustible mixture of gas and air from manifolds 24that are connected through conventional conduits and gas control valves(not shown) to a gas source (not shown).

Baffies 27 and 28 are provided for protecting burners 23 from airentering box 17 through nozzle 21 to prevent chilling or unevencombustion in the burners. Each of boxes 17 is also provided, at itsoutlet end, with another bathe in the form of an air blade supplied byan air knife assembly 29 to directing solvent laden air from adjacentthe web surface into outlet duct 22, thereby blocking flow of suchsolvent laden air from each heating chamber to the next adjacent heatingchamber 17. In the case of the last heater box of each linear array ofboxes, the air knife assembly 29 functions to block flow of solventladen air from the end of the array.

Considering now FIGURES 1 and 2, the inlet ducts 20 and outlet ducts 22are parts of means defining a cyclic flow path for carrying a cyclicstream of air, said means including a manifold 31. The cyclic stream ofair is cycled through the heater boxes 17 from their inlet ducts 20- totheir outlet ducts 22 in parallel flow. A conduit in the form of a drop30 is provided for communicating recirculating manifold 31 with theinlet duct 20 of each chamber. Each drop 30 is divided by partitions311a into four separate conduit sections, best seen in FIG- URE 5, eachwith a separate adjustable balance damper 32 for controlling flow of airthrough the drop 30- to provide an even discharge of air from nozzle 21across the web surface within the box 17. A recirculating fan 33communicates with '31 for circulating air through duct 31 and into drops30.

Each outlet duct 22 from a heating chamber 17 is seen in FIGURE 4toenter the lower end of a drop 30 alongside the inlet duct 20 of the nextadjacent chamber 17, and a transverse wall 22a defines the top of eachof the ducts 22 which then pass transversely out of the drops 30 andthrough return ducts 36 to a return manifold 37 which feeds the lowpressure side of an exhaust fan 38. The exhaust air is laden withsolvent vapor and is forced by the fan 38 through a catalytic combustionchamber 39 which contains burners 39a and a plurality of catalyst masses411 through which the air passes to catalytioally remove the solventvapor from the air.

Flow of desolventized air from the chamber 39 is divided between areturn air supply conduit 43 which feeds the low pressure side ofrecirculating fan 33, and an exhaust system, indicated generally at 44,with distribution of air between the supply conduit 43 and the exhaustsystem 44 controlled by balancing dampers including an adjustablerecirculating damper 41 and an adjustable exhaust damper 42.

The exhaust system 44- includes a tube-type heat exchanger 4-4a wherethe air passes through a plurality of tubes and is then exhausted to theatmosphere through a stack 45. The heat exchange tubes of the heatexchanger 44 are in heat exchange relationship with a mass of aircirculated from a make-up air collecting fan 46 through a balancingdamper system 46a which controls distribution of fresh air selectivelyto a plenum 47 of the heat exchanger 44a or to a bypass conduit 47a,both of which feed into a duct 48 that supplies properly heated air tothe press room.

The exhaust damper 42 is fully open and the recirculating damper 41 isfully closed when the dryer system is first started up, and for dumpingall air to the atmosphere in case of shut-down of the equipment. Therecirculating damper 41 is operated to open only when the exhausttemperature from catalytic combustion chamber 39 is up to a presettemperature, e.g. 550 F., at which point the exhaust damper 42 is partlyclosed to permit the recirculating air fan 33 to circulate apredetermined percentage of the heated air from the chamber 39 throughthe heating chambers 17. Also, a cold air damper 43a is provided in thewall of return air supply duct 43, and may be opened to quickly cool therecirculating manifold 31 and the heater boxes 17 in case of a pressshut-down.

Thus, it is seen that a cyclic stream of heated air is provided fromcatalytic combustion chamber 39 through duct 43, fan 33 and manifold 31to drops 30 and heating chambers 17, thence through the heating outletducts 22 and return ducts 36 for return through manifold 37 and exhaustfan 38 to catalytic combustion chamber 39. Continued Withdrawal of aportion of the air is provided by control of damper 42 to permit therecirculating air stream to draw in additional air at various positionsin the total system as will be more evident hereinbelow.

Referring now especially to FIGURES 3 and 5, it is seen that each of theair knife assemblies 29, heretofore referred to, for directing an airblade against the web surface, is mounted in the lower end of an exhaustduct 22 and is supplied with high pressure air from a supply conduit 50which communicates with a transverse air tube 51 having a linear arrayof ports 52 which discharge the high pressure air into an air directingassembly 53 that is mounted on brackets 57 within the outlet duct 22.The air directing assembly 53 comprises a pair of spaced walls 54 whichconverge at their lower edges in an elongated air directing nozzle 55that is generally in line with the array of ports 52 and has generallyparallel walls. High pressure air from ports 52 is directed throughnozzle 55 as a blade of air extending the width of the web where the webpasses over roller 13, thus blocking the flow from chamber 17 of gasesentrained by the web W as it traverses the open side 19 of the heatingchamber and diverting the gases into outlet duct 22.

Turning now to FIGURES 1, 3, 6 and 7, the burners 23 are elongate inshape, each of a length generally the width of the heating chamber 17and each containing a linear array of burner heads 58 that are suppliedwith gas and air from the manifold 24. The manifold 24 extends generallyalong the top of each burner 23 and is supported in heater box 17 bysuitable mounting means (not shown).

Referring now especially to FIGURES 6 and 7, each of the burner heads 58includes a threaded tubular fitting 59 which is screwed into a hole inmanifold 24 and impales a burner casing member 62 to hold the casingbetween an external flange 60 on fitting 59 and a washer 61 which spacesthe casing 62 from manifold 24. The casing 62 extends the length ofburner 23 and is provided with a pair of opposed downwardly and inwardlyturned flange portions 62a which support an elongated trough-like burnercup 63 that also extends the length of burner 23 and is composed of arefractory material such as a dense fire brick.

Each fitting 59 in trough 63 carries a refractory burner tip member 64mounted on a threaded stud 67. The threaded stud 67 is received in afemale threaded member 68 that bridges and is threaded within aninterior cavity 59a of fitting 59. The bridging member 68 includes aplurality of ports 69 so that a combustible mixture of air and gas mayflow from manifold 24 through fitting 59 and between radial ribs 64a onnozzle tip 64 into the interior of trough 63 and burn therein.

The air baffle 27 is clamped between manifold 24 and burner casing 62 asseen in FIGURES 6 and 7, while baffle 28 is mounted on baffle 27. As iscustomary in dryers of the present type, the manifolds 24 are journalledfor r0- tation so that when the web W is stopped, the burners may beinverted to prevent scorching the paper.

A screen member 70 is provided for covering the entire open lower sideof trough 63, and includes a pair of opposing upwardly and inwardlyturned flange portions 70a which snap into a pair of outwardly facingcomplementary grooves 63a adjacent the lower edges of the trough.

In the burner arrangement, it will be noted that the burner nozzledelivers gas between member 64 and fitting 59 in a lateral direction. Itis to be understood, of course, that the gas may be fed directly againstthe screen 70' if desired. In either instance, the screen helps toanchor the flame to the burner nozzle and maintain the flame within thelimit of trough 63 to inhibit direct contact of the flame with the web,and also spreads the heat from the several spaced burner heads 58relatively evenly across the web.

The screen 70 may be selected as desired with respect to gauge andmaterial of composition; however, it is preferred that the screen bemade of a metal capable of infrared radiation when heated by the burnernozzle. For example, Nichrome screens are acceptable, and the screenused in the illustrated form is an 8 x 8 mesh, .063 diameter wirescreen. The screen should be of suflicient gauge not to burn out at thetemperature to which it is heated by the burner.

Although smaller, individual screens could be provided for each burnernozzle, the elongate screen supported along its edges is preferred sinceit has been found that the upstanding screen flanges give the screenadditional rigidity so as not to bow and wipe against a web passingbeneath the heating chamber 17. The web surface passes in close spacedproximity to screen 70. Further, the continuous trough-type heater cupis preferred because it gives better heat distribution across the web.

Referring now to FIGURE 3, below each of the heating chambers 17 andbeneath the web W there is provided a casing 73 that is mounted onsuitable framework and defines an air receiver 74. The air receiver 74is connected by suitable duct work with return manifold 37 (FIGURE 2).Each of air receivers 74 includes an inlet opening 75 extending thewidth of the web for drawing air adjacent the web into the receiver 74.An upstanding wall 76 of casing 73 behind the opening 75 is very closeto the web W and functions as a baffle to help direct air into receiver74. An additional baflle is provided in the form of an air knife 77, ofgenerally the same construction as air knife 29 and supplied with airunder pressure from the same air source. Air knife 77 is directedagainst the lower surface of web W to block flow of air entrainedadjacent said lower surface and divert such air, which may containsubstantial amounts of volatile solvents, through inlet 75 in thereceiver 74.

In addition to the air receivers 74, a casing 78 adja- 6 cent each drum14 defines an exhaust chamber 79 (FIG- URE 8) at the end of each array11 or 12 of heating chambers 17 for collecting solvent laden air whichmay have escaped from the chamber 17, and also solvent vapor which boilsout of the ink after the web leaves the heater array, due to latent heatin the web. Casing 78 is mounted on brackets 80. Each casing 78 includesa plurality of elongate slots or openings 81 extending the width of theweb W. Upstanding flange means define an intake throat 82 for eachopening 81. A throat extension member 83 is telescopically received ineach throat 82 and includes an outer lip 84 in the form of an outwardlyand downwardly turned flange. The throat extension member 83 is tightlyslidable in the intake throat 82 and is adjustable toward and away fromthe web travel position so that the lip end 84 may be disposed in closeproximity tothe lower face of the web. The downwardly turned edgeportions of the lip end 84 tends to bafl'le gases traveling along withthe under surface of web W to a position between lip end 84 and the weblower surface to be drawn inward to opening 81. This configuration oflip end 84 also permits close association of the lip end 84 with the webwithout fear of tearing by exposed lip edges. An additional intakeopening 87 is provided adjacent the drum 14 to draw air into casing 78from the diminishing space between the web and roller and thus preventany escape of solvent laden air which might otherwise condense on drum14.

Chamber 79 is connected by an outlet duct 88 into the return manifold37.

During operation of the device, air is drawn from air receivers 74 andexhaust chambers 79, thereby drawing gases from adjacent the lowersurface of the web into the chambers and into the cyclic stream of air.Such removal of gases from the lower surface of the web serves todecrease room contamination and also serves to reduce the tendency ofthe volatilized solvents to condense and collect on rollers 13 and drums14. Thus, air is permitted to enter the cyclic stream of air via theinlets to air receivers 74 and exhaust chambers 79, as well as betweenthe edges of casing 18 defining open side 19 and the deb W, so thatmake-up air for the system is drawn out of the press room in which thedryer is operated.

Condensation forming on duct work within the system has also beenminimized because the over-all temperature in the heater boxes and inthe duct work is maintained by the air heater 39 above a temperaturepermitting such undue condensation, maintaining the solvents vaporizedand in suspension. Very little condensation has been encountered.

As another advantage, the product delivered from the system using therecirculating air as described herein was discovered to have increasedgloss. It is believed that this occurs from recirculated air temperingthe heat of the burners and eliminating hot spots which may tend to burnthe varnish from the ink. Further, the tendency of the web to dryunevenly has been decreased and less hot spots are formed across thewidth of the web. The air directed over the printed surface of the webprovides a surface cooling effect during drying to slow the drying ofthe surface portion of the ink. Also, radiant energy from the burnersand from the screens is permitted to penetrate to the interior of theink film to vaporize the solvents therefrom. By not hardening thesurface of the ink film immediately, the vaporized solvents arepermitted to escape from the interior of the ink film before the outerskin of the film hardens, thereby giving a better dried ink surface.

We claim:

1. A system for drying a still wet ink printed web surface, which systemcomprises means defining a plurality of aligned heating chambers eachhaving an open side, the open sides of said chambers being in lineararray, burner means in each chamber, means for directing the web withthe still wet printed surface facing and adjacent said array of opensides in direct heat receiving proxirnity to said burner means from aweb entry end of said array to a web exit end thereof, said directingmeans including means beyond the exit end of said array for directingthe web away therefrom, means defining an exhaust chamber spaced fromthe web other surface adjacent the exit end of said array, a pluralityof openings in the exhaust chamber extending across and facing the web,means associated with each of said openings for conducting air throughthe opening from adjacent the web surface, said associated means beingselectively adjustable toward and away from the web surface, meanscarried at the outer ends of said associated means adjacent the websurface defining an outwardly flared lip for preventing contact of theweb with exposed edges of said associated means, said outwardly flaredlip being of a configuration directing entrained air adjacent the websurface into said associated means, additional opening means in saidexhaust chamber disposed adjacent said web directing means beyond saidexit end for receiving entrained air from said directing means and fromthe web surface, and air exhaust duct means for conducting air from saidexhaust chambers.

2. A system for drying a still wet ink printed web surface, which systemcomprises means defining a plurality of aligned heating chambers eachhaving an open side, the open sides of said chambers being in lineararray, burner means in each chamber, means directing the web with thestill wet printed surface facing and adjacent said array of open sidesin direct heat receiving proximity to said burner means along said arrayof open sides from a web entry end of said array to a web exit endthereof, an inlet manifold for said heating chambers, an exhaustmanifold for said heating chambers, means for introducing secondary airfrom said inlet manifold at a first end of each chamber adjacent the webat said web entry end and for directing introduced air toward the webexit end of each chamber, exhaust duct means at said second end of eachchamber for conducting air to said exhaust manifold, air knife meanscomprising a pair of spaced converging baffles at said second end ofeach chamber for directing air as a thin elongate blade configurationtransversely impinging the web to block fiow of entrained air with theweb beyond the second end of said chamber and to direct the entrainedair into said exhaust duct means, and means supplying high pressure airto said air knife means between said converging baffles toward the web.

3. A system for drying a still wet ink printed web surface, which systemcomprises means defining a plurality of aligned heating chambers eachhaving an open side, the open sides of said chambers being in generallylinear array, open burner means in each chamber, means for directing theweb with the still wet printed surface in direct heat receivingproximity to said burner means along said array of open sides from a webentry end of said array to a web exit end thereof, air receiver meansopposing each of said heating chambers beyond said web and facing theopposite surface of the Web, air knife means comprising a pair of spacedconverging baflies for directing air to a thin elongate bladeconfiguration for impinging the web opposite surface for directingentrained gases from said surface to said air receiver means, and meanssupplying high pressure air to said air knife means between saidconverging baffles in a direction toward the web to form said blade,whereby any gases entrained by the web from said heating chamber andadjacent said web opposite surface are diverted to said receiver.

4. A system for drying an ink printed web 'after printing of the web oneach surface, which system comprises means defining a first plurality ofheating chambers with aligned open sides, means defining a separatesecond plurality of heating chambers with aligned open sides, means fordirecting a flexible web with a newly printed one of two opposingsurfaces facing the aligned open sides of said first plurality ofchambers, thence away from said first plurality of chambers for printingthe other surface and thereafter as a continuous web with the other websurface facing the aligned open sides of said second plurality ofchambers, said directing means including means engaging the outer websurface relative to said chambers for holding said web with the innersurface closely facing the aligned open sides of said pluralities ofchambers, burner means in each heating chamber facing the open sidethereof, screen means snap-lock mounted on said burner means forprotecting the web surface at said web travel position from burning,means downstream relative to web travel direction from the last alignedchamber of each plurality for. directing the web away therefrom, conduitmeans defining a cyclic air flow path for flowing air as a cyclic streamin parallel through each heating chamber from a chamber inlet to achamber outlet, air knife means comprising a pair of spaced convergingbafiles adjacent to each chamber outlet directing air from a highpressure air source to a thin elongate blade configuration impinging theweb substantially the extent of web width, said air knife means beingdisposed to block flow of air with the web beyond the web exit end ofsaid chamber and to direct blocked air away from said web travelposition for exhausting through the chamber outlet, means for heatingair and removing ink solvents therefrom in said conduit means and cyclicflow path, air receiver means associated with said heating chambersbeyond said web position and facing the outer web surface and the openside of the heating chambers, air knife means comprising a pair ofspaced converging baffies for directing air to a thin elongate bladeconfiguration for impinging the web outer surface for divertingentrained air into said air receiver means, means supplying highpressure air from a high pressure air source to each air knife meansbetween said converging bafiles in a direction toward the convergingedges thereof, means defining an exhaust chamber spaced from web outersurface beyond the last chamber of each plurality of aligned chambers, aplurality of exhaust chamber inlet openings spaced in the direction ofweb travel and extending approximately the web Width, means associatedwith each of said openings for conducting air through the opening fromadjacent the web outer surface, said associated means being selectivelyadjustable toward and away from the web for positioning said associatedmeans in a proper receiving position closely spaced from the web, meanscarried at the outer ends of said associated means for preventingcontact of the outer web surface with exposed edges of said associatedmeans and for directing entrained air adjacent the web into saidassociated means, additional inlet opening means in said exhaust chamberdisposed adjacent said downstream web directing means for receivingentrained air from the web outer surface at said directing means, andair receiver duct means for conducting air from said air receivers andexhaust chambers to said cyclic stream.

5. A system for removing entrained gases from adjacent the undersurfaceof a traveling web which is supported on rollers, which systemcomprises: means defining an air receiver; first inlet means for saidreceiver below the plane of the web; conduit means extending beneath theweb and communicating at one end with said inlet means, said conduitmeans being adjustable toward and away from said web for disposing theother end of said conduit means adjacent said web, suction means fordrawing entrained gases through said inlet means and into said receiver;and second inlet means for said receiver having an open entry end closeadjacent the area where the web approaches and passes over a roller,whereby gases trapped in the diminishing space between the web and theroller surface may be drawn into said second inlet means.

6. A system for removing entrained gases from adjacent the undersurfaceof a traveling web which is supported on rollers, which systemcomprises: means defining an air receiver; a plurality of first inletmeans for said receiver below the plane of the web and spaced along theweb; open conduit means extending beneath the web telescoped in each ofsaid first inlet means, said first inlet means being telescopicallyadjustable toward and away from said web surface; suction means fordrawing air through said inlet means and into said receiver; meanscarried by said open conduit means for directing entrained gases intosaid open conduit means; and second inlet means for said receiver in thedirection of web travel from said first inlet means, said second inletmeans having an open entry end close adjacent the area where the webapproaches and passes over a roller, whereby gases trapped in thediminishing space between the web and the roller surface may be drawninto said second inlet means.

7. A system for drying an ink printed web after print ing of the web oneach surface, which system comprises: means defining a first pluralityof heating chambers with aligned open sides; means defining a separatesecond plurality of heating chambers with aligned open sides; burnermeans in each heating chamber-facing the open side thereof and includingan elongate refractory trough having an open side close adjacent and inunobstructed facing communication with the chamber open side, gas andair supply means for supplying gas and air to a plurality of burnerpositions spaced longitudinally within each trough, a burner at eachburner position for receiving gas and air from the supply means anddelivering gas laterally within each trough, and separate screen meansdetachably secured to each trough and spanning and enclosing the openside of each trough; and means for directing a con tinuous flexible web,which has been newly printed on a first surface, along the aligned opensides of said first plurality of chambers to substantially enclose saidchambers with said newly printed first surface exposed to heat andcombustion gases from said burner means, thence away from said firstplurality of chambers to a position for printing the second surface andthereafter along the aligned open sides of said second plurality ofchambers to substantially enclose said second plurality of chambers Withsaid newly printed second surface exposed to heat and combustion gasesfrom the burner means in said second chambers.

8. The combination of claim 7 in which the directing means includes aplurality of spaced chill rollers immediately adjacent the heatingchambers and engaging the web surface which faces away from thechambers.

References Cited UNITED STATES PATENTS 2,095,471 10/1937 Hayward15-306.1 2,204,801 6/1940 Gessler 34-68 X 2,204,802 6/ 1940 Gessler34-23 X 2,268,985 1/1942 Hess 34-23 X 2,268,896 1/1942 Hess et al. 34-232,268,988 l/1942 Hess et al. 34-23 X 2,354,893 8/1944 Thoma.

2,533,104 12/1950 Golden et al. 158-99 2,803,446 8/1957 Flynn 263-32,837,830 6/1958 Fry et a1. 34-23 2,855,190 10/1958 Rieger 263-32,884,705 5/1959 Flynn 34-23 2,956,300 10/1960 Bruno 15-306.1 3,027,9354/1962 Sobole 158-99 3,150,864 9/1964 Fetner et al. 34-4 X FREDERICK L.MATTESON, JR., Primary Examiner. C. R. REMKE, Assistant Examiner.

1. A SYSTEM FOR DRYING A STILL WET INK PRINTED WEB SURFACE, WHICH SYSTEMCOMPRISES MEANS DEFINING A PLURALITY OF ALIGNED HEATING CHAMBERS EACHHAVING AN OPEN SIDE, THE OPEN SIDE OF SAID CHAMBERS BEING IN LINEARARRAY, BURNER MEANS IN EACH CHAMBER, MEANS FOR DIRECTING THE WEB WITHTHE STILL WET PRINTED SURFACE FACING AND ADJACENT SAID ARRAY OF OPENSIDES IN DIRECT HEAT RECEIVING PROXIMITY TO SAID BURNER MEANS FROM A WEBENTRY END OF SAID ARRAY TO A WEB EXIT END THEREOF, SAID DIRECTING MEANSINCLUDING MEANS BEYOND THE EXIT END OF SAID ARRAY FOR DIRECTING THE WEBAWAY THEREFROM, MEANS DEFINING AN EXHAUST CHAMBER SPACED FROM THE WEBOTHER SURFACE ADJACENT THE EXIT END OF SAID ARRAY, A PLURALITY OFOPENINGS IN THE EXHAUST CHAMBER EXTENDING ACROSS AND FACING THE WEB,MEANS ASSOCIATED WITH EACH OF SAID OPENINGS FOR CONDUCTING AIR THROUGHTHE OPENING FROM ADJACENT THE WEB SURFACE, SAID ASSOCIATED MEANS BEINGSELECTIVELY ADJUSTABLY TOWARD AND AWAY FROM THE WEB SURFACE, MEANSCARRIED AT THE OUTER ENDS OF SAID ASSOCIATED MEANS ADJACENT THE WEBSURFACE DEFINING AN OUTWARDLY FLARED LIP FOR PREVENTING CONTACT OF THEWEB WITH EXPOSED EDGES OF SAID ASSOCIATED MEANS, SAID OUTWARDLY FLAREDLIP BEING OF A CONFIGURATION DIRECTING ENTRAINED AIR ADJACENT THE WEBSURFACE INTO SAID ASSOCIATED MEANS, ADDITIONAL OPENING MEANS IN SAIDEXHAUST CHAMBER DISPOSED ADJACENT SAID WEB DIRECTING MEANS BEYOND SAIDEXIT END FOR RECEIVING ENTRAINED AIR FROM SAID DIRECTING MEANS AND FROMTHE WEB SURFACE, AND AIR EXHAUST DUCT MEANS FOR CONDUCTING AIR FROM SAIDEXHAUST CHAMBERS.